Members of the PSL provide consulting services in several areas of applied mathematics and the physical sciences to researchers at NIH and elsewhere. We have completed a study on the phantom view method in computerized tomography, finding that it is effective at diminishing certain undesireable streak artifacts. A considerable amount of work was spent on the study of aduiologic defects in patients with osteogensis imperfecta. An analysis of post traumatic epilepsy in head-injured Vietnam veterans is being completed and a model that fits data very well on the rate of occurrence of fits has been developed. A mathematical model for the entrance of drug addicts into treatment facilities was devised and shown to given an excellent fit to available data. Several combinatorial problems related to computer storage were solved to yield asymptotic formulae.